Vaccinating Frogs

Endangered Species
Biodiversity
Environmental & Science Education
Behavior
by Edward Hessler
The number of extinctions of frog populations worldwide due to fungal infections may surprise you. It did me. The number is 200 and growing.
It is a serious skin ailment caused by the chytrid fungus. Frogs die within a few weeks upon being infected. The importance of a frog's skin to its life is not to be underestimated. It allows them to be a frog. The skin is the organ through which frog's breathe as well through which chemicals important to their survival--e.g., fluid balance--are absorbed.

Photo of yellow-legged frog by Isaac Chellman, NPS
via Wikimedia Commons

Recently scientists have turned their attention to the frog's immune system, trying to "trick" it by making it just sick enough to build their immunity to the fungus.  The experimental treatment is being conducted with yellow-legged frogs which are found in alpine lakes of the Sierra Nevada mountains. About 90 percent of this population has disappeared.
The experimental therapy is nearing the end of its third summer and there is reason for hope since survival has been surprisingly good.  If the treated frogs survive for a few seasons they may be able to survive and grow in the long-term, as the great force of natural selection takes over and directs their evolution. But this will take time.
NPR reporterLauren Sommer told the story of this research effort September 10. A short film about it from the WQED and PBS "Deep Look" series is also embedded in the story.